Process for removing models from dentures



March 8, 194-9. uzz 2,464,140

PROCESS FOR REMOVING MODELS FROM DENTURES Filed May 17, 1945 flaaaar/fy (/2 27 IN VEN TOR.

Patented Mar. 8, 1949 PROCESS FOR REMOVING MODELS FROM DENTURES August F. Luzzi, Wichita Falls, Tex., assignor to E. R. Rinehart, Jr., Fort Worth, Tex.

Application May 17, 1945, Serial No. 594,209

3 Claims. 1

This invention relates to a method for the removal of models from dentures after having been processed and deflasked.

The principal object of the invention is to improve upon the conventional methods of removing models from dentures by substituting for the laborious and tedious practice of chipping the model out from undercuts of the denture, a more facile method wherein an impression is made in the model in the form of a cavity having plurality of lateral or radial grooves defining corresponding webs or sections which are more readily broken out by wedging force as applied by a flat instrument such as a screw driver or the like.

With the foregoing objects as paramount, the invention has further reference to certain features of accomplishment which will become apparent as the description proceeds, taken in connection with the accompanying drawings wherein:

Figure 1 is a perspective view of a spider forming a part of the model remover of the invention.

Figure 2 is a perspective view showing the spider being removed from a model and Figure 3 is a perspective view of the step of breaking out the Webs formed in the model by the spider.

Continuing with a more detailed description of the drawing, reference is primarily made to Figure 1 wherein numeral Ill denotes a molded or cast body of metal or plastic, from whose major axis protrude three or more lateral arms or prongs I I. The under-surfaces of these arms are formed into tapered or wedge shaped fins l2, curved at a to correspond approximately to the curvature of a denture not shown, which may be attached to the model l3 (Figs. 2 and 3).

Spaced along the length of one of the arms l I are minor arms or projections 14 whose undersides also conform generally to the contour of the denture. At the approximate center of the body H], which may be hereinafter referred to as the spider, is a threaded opening l5a, to which further reference will be made presently.

Figures 2 and 3 show bottom views of a model after the spider has been removed. The major grooves I6 in the model were formed by the arms ll of the spider while minor grooves H were formed by the protuberances M of the spider at the time the impression was poured. It will be observed that the webs defined by the grooves have upwardly converging walls, due to the tapered walls of the arms of the spider.

To carry out the steps of the method, a spider is selected of such size that it can be placed into the conventional impression tray without binding at the sides and the threaded hole l5a is plugged at the top and bottom with a thin piece of ordinary base plate wax to prevent the model material from entering the same.

Now, an impression is made of the mouth in the usual manner by a tray, and this impression is poured using plastic model material such as plaster or artificial stone, after which the spider is placed in position in the impression tray. Then a small fiat surface, such as a piece of glass, is placed on top of the spider and the impression tray with all of its contents is inverted and the plastic model material is brought against the sides of the impression tray to shape the sides of the model.

After the model has hardened, the impression tray is separated from the model and the palatal portion of the denture, bearing the teeth is set upon the model in the usual manner. Subsequent to the steps of processing and defiasking, the plastic material is scraped from the top of the spider to expose the hole I5a, then the spider is removed, leaving the model in the condition shown, to be broken out in sections.

Figure 2 shows the preferred instrument for removing the spider from the model. This instrument consists of a conventional slide hammer including a rod 18, on which is reciprocably mounted a hammer 19 of cylindrical shape. One end of the rod is threaded to be received in the threaded opening l5a of the impression spider Ill and the opposite end of the rod carried a head 20. By reciprocating the hammer l9 lightly against the head 20, the spider is dislodged from its sunken position in the model and is cleanly removed, leaving the model with the cavity and grooves, as shown.

To remove the model from the denture on the opposite side from that shown in Figures 2 and 3, an instrument 2|, such as a common screw driver or the like, is first placed in the lowermost groove, in the position shown in Figure 3. By a wedging action imposed by the instrument, sections of the model, identified as b and c are broken out. However, if only section b is broken out, the instrument is placed in the opposite end of the groove and further wedging force will release section 0. Further manipulation of the instrument 2| in appropriate points throughout the impression will eventually remove all sections of the model cleanly and in but a fraction of the time usually required for painstakingly 3 chipping the artificial stone model from the denture in the conventional manner.

The important feature of the invention is that a very hard artificial stone model can be easily removed from a denture with definite undercuts without damage to the denture.

Manifestly, the construction and process as shown and described is capable of some modification and such modification as may be construed to fall within the scope and meaning of the appended claims is also considered to be Within the spirit and intent of the invention.

What is claimed is:

1. In the hereindescribed process for removing models from dentures,- characterized ,by initially making an impression of a mouth, in

pouring the material of the ,model in a plastic.

state in an impression tray about a spider, removing the spider from the model upon hardening of said material to define a multi-grooved cavity in the model in mounting a denture on the model and finally in breaking out the elevated sections of said model as defined by the grooves of said cavity.

2. In the hereindescribed process for removing models from dentures, the steps of initially obtaining a mouth impression in pouring the material of the model about a multi-pronged spider 4 in an impression tray, in mounting a dentur on the model, in removing said spider after said material has set, and finally in breaking out the webs in the model defined by the prongs of said spider.

3. In the process for forming and removing models from dentures, the steps of initially obtaining an impression of the mouth with an impression tray, in pouring the plastic material of the model about a multi-pronged spider set in said tray, in allowing the material to harden, in

attaching a denture to the model, in removing the spider and finally in imposing a wedging action between webs in the model defined by the spider to break out the model in sections.

AUGUST F. LUZZI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Chamblin July 30, 1940 

